Previous studies have shown that succimer is a soft tissue chelator of lead; therefore, potential neurobehavioral health benefits may be expected. However, most of the published studies focused their attention toward succimer's ability to reduce blood lead level without evaluating its impact on neurobehavioral health. The proposed cross-sectional study is designed to evaluate the fine motor and gross motor proficiency as well as postural balance and gait in 200 children [from the Cincinnati Clinical Center for Treatment of Lead in Children (TLC)] who are currently active in a randomized double blind clinical trial designed to assess the effects of lead chelation using the drug succimer. In the proposed study, we will be assessing postural balance and gait and fine and gross motor development after the TLC children have completed their succimer or placebo program and the TLC follow-up period. The postural balance and gait and fine and gross motor assessments will be carried out with established techniques which have been used by us over 13 years on the Cincinnati Lead Program Project (LPP) cohort. The postural balance and gait will be assessed with a microprocessor-based force platform system along with a test protocol which indirectly assesses the roles of various physiological systems relevant for postural balance. The fine motor and gross motor assessments will be carried out using the comprehensive Bruininks-Oserestsky Test of Motor Proficiency (BOTMP) test battery. The TLC clinical trial of succimer is focused mainly on global measures of cognitive development. Assessments of motor development in the gross and fine motor spheres, postural balance and locomotion are not emphasized. Thus, this study will make a unique contribution to our understanding of the developmental benefits of chelation therapy and other measures to reduce lead in the range of exposures that are being considered. Our published findings from Cincinnati LPP cohort with the proposed motor development measurement instrument (BOTMP), postural balance test and locomotion test indicate that these measurement techniques are sensitive and, compared to cognitive measures are relatively uninfluenced by socioeconomic cofactors. Thus, the project has significance for furthering out understanding of the clinical benefits of succimer on developmental aspects of postural balance, locomotional outcomes and fine and gross motor functions in the developing central nervous system in socioeconomically disadvantaged populations.